Download The Relationship between Photosynthesis and Cellular Respiration

Where do we get
our energy from?
Photosynthesis: An Overview
Some details:
Water
Sunlight
Light
Reaction
ATP
Carbon
Dioxide
NADH
Dark Reaction
Glucose
Oxygen
Today’s Goal!
To explain how energy is
transferred from sunlight to
glucose via the light and dark
reactions of photosynthesis.
The Formula for
Photosynthesis
THE CHLOROPOPLAST
Light dependent and light
independent reaction locations
Inner and outer
membrane of
chloroplast
Stroma
Thylakoids
(Light INDEPENDENT)
(Light DEPENDENT)
CALVIN
Pigments- Important for the
absorption of light energy
Three types:
1. Chlorphyll a- absorbs all spectrum of light
except for green
2. Chlorophyll b- absorbs most spectrum of
light except orange, yellow or red
3. Carotene- absorbs most spectrum of light
except for orange
So why are
plant leaves
green?
Another Question: Why
are leaves a different
color in the fall? See the
next slide for the answer
from a celebrity presenter.
1. In the Fall the strength of the sun
decreases.
2. Plants will decrease their
production of chlorophyll a in
order to conserve more sugar for
the winter months. (remember
that when the body builds
something it requires energy)
3. The remaining pigments will
reflect different spectrum of light
depending on the species.
Hey! Its David
Ortiz…maybe he can
explain why the leaves
change color in the fall.
Thanks David!
Light Reactions-Does this picture
look familiar?
Electron Carriers
What do they do?
• Electron carriers take high energy
electrons (stored on H) and bring them to
electron transport chains (more on these
later)
• The electrons become high energy when
exposed to sunlight
Examples:
1. With electronsNADPH or FADH2
2. Without electrons NADP+ or FAD+
Light Reactions
e- e- ee- eee1. Sunlight hits
chlorphyll and
excites the
electrons (woo
hoo!)
Really
excited
electrons
+
NADP+
NADPH
FAD+
FADH2
Electron
carriers
2. These electrons
are transferred to
electron carriers
ee- ee- e-
H+’s used to help
carry electrons
(FAD+ becomes
FADH2 when it
carries electrons)
H+
H+
Excited
electrons
splitting H20
molecule into
its base
elements
O- leaves the
plant via
stomata
3. These electrons
are used to split
water molecules
(this is why plants
produce oxygen)
This is a close-up shot of the pathway the light
energy traveled…from beginning to end.
The Electron Transport Chain is represented by the dashed line and has
one side which is highly positive…shooting the Hydrogen ions against
the positive gradient creates energy.
+
+
++
+
+
+
+
+
------------------H+
H+
H+
H+
H+
H+
H+
4. These Hydrogen ions are also
shot across an electron
transport chain (against the
proton gradient…remember
the sledding example)
H+
Energy from electron
transport chain
ATP
Note the H+ ions returning
through ATP
Synthase…Oxygen picks up
these ions and forms
H20…more on this when we
get to cellular respiration
SYNTHASE
ADP + P
ATP
5. This produces enough energy to make
a small amount of ATP which will be
used in the Calvin Cycle
This is a close-up shot of the pathway the light
energy traveled…from beginning to end.
Light-dependent Reaction-Takes
Place in Thykaloid
1. Sunlight hits
chlorphyll and excites
the electrons (woo
hoo!)
2. These electrons are
transferred to
electron carriers
3. These electrons
are used to split
water molecules
(this is why plants
produce oxygen)
4. Hydrogen ions are also
shot across an electron
transport chain (against
the gradient…remember
the sledding example)
5. This produces
enough energy to
make a small
amount of ATP
which will be used
in the Calvin Cycle
Dark Reactions (Calvin Cycle)
CO2
CO2
CO2
CO2
CO2
CO2
Plant taking in
CO2
Lets zoom
in
Electron
micrograph photo
of stomata(s)
1. The plant “breaths in” C02 via stomata
Energy from ATP
and NADPH
Carbon Dioxide
being split into
base elements
O- C
O-
2. The ATP and NADPH
produced in the light reaction is
used to break apart the CO2 into
its base elements
Carbon’s
from
Carbon
Dioxide
Oxygen’s from the
splitting of H20
OOO-
OO-
O-
+
C
C
C
C
C
C
+
Hydrogen’s
from the
splitting of
H20
H+ H+
H+
H+ H+
H+
H+ H+
H+
H+ H+ H+
C6H12O6
Aka:
Glucose
3. With enough C02 and H (remember when
the water molecule was split?) a glucose
molecule is formed (what was that formula
again?)
The processes we
have talked about
are how carbon and
energy enter the
food chain.
Calvin Cycletakes place in Stroma
1. The plant
“breaths in”
C02
2. The ATP and
NADPH produced
in the light
reaction is used to
break apart the
CO2 into its base
elements
3. With enough C02
and H (remember
when the water
molecule was split?)
a glucose molecule is
formed (what was
that formula again?)
Using your notes and the diagram below, explain how
energy is transferred from one form (Sunlight) to one
that is stored (Glucose). Use the reactions involved in
Photosynthesis in your explanation.